The invention relates to a method and device for roll stabilization of a motor vehicle wherein on the basis of a measured transverse acceleration or a calculated transverse acceleration of the motor vehicle, actuating signals are generated for actuators that are associated with a front axle and a rear axle of the motor vehicle and provide support torques on the front axle and/or on the rear axle for roll stabilization of the motor vehicle.
The driving characteristics of a motor vehicle are determined by a number of forces and torques which act on the motor vehicle in the direction of the vehicle axes, namely, in the direction of a longitudinal axis, a transverse axis, a vertical axis, and a roll axis. The roll axis is understood to mean an axis extending through roll centers of the front axle and the rear axle of the motor vehicle. A rolling motion of the motor vehicle about the roll axis is referred to as roll. To provide satisfactory driving characteristics of a motor vehicle, it is known from the prior art to implement roll stabilization on the motor vehicle. Roll stabilization based on the driving state is characterized in that, for example, by a measured transverse acceleration or a calculated transverse acceleration of the motor vehicle, actuating signals are generated for actuators which are associated with the front axle and the rear axle of the motor vehicle and which provide support torques on the front axle and/or on the rear axle for roll stabilization. The actuators are typically hydraulically displaceable stabilizers, which may be actuated by valve blocks. The valve blocks receive actuating signals from a control and regulation device, which on the basis of the measured or calculated transverse acceleration of the motor vehicle generates the actuating signals.
In the known roll stabilization, as previously stated, support torques are provided on the front axle and/or on the rear axle for roll stabilization, in which a torque distribution between the support torque provided on the front axle and the support torque provided on the rear axle influences the so-called self-steering effect of a motor vehicle.
When the motor vehicle is subjected to alternate loads, the self-steering effect of the motor vehicle may change such that a desired user-friendly driving characteristic of the motor vehicle can no longer be ensured. No method or device for roll stabilization of a motor vehicle is known, heretofore, which addresses this problem.
Proceeding from this situation, the object of the present invention is to provide a novel method and a novel device for roll stabilization of a motor vehicle.
According to the invention, to ensure a satisfactory self-steering effect of the motor vehicle, a torque distribution between the support torque provided on the front axle and the support torque provided on the rear axle is modified on the basis of a first signal which allows conclusions to be drawn concerning the actuation of a gas pedal or increased drag torque, and/or on the basis of a second signal which allows conclusions to be drawn concerning the actuation of a brake pedal.
Within the scope of the present invention, for the first time a method for roll stabilization of a motor vehicle is provided, in which to ensure a satisfactory self-steering effect of the motor vehicle, the torque distribution between the support torque provided on the front axle and the support torque provided on the rear axle is modified as a function of the actuation of the gas pedal, of the drag torque, and/or of the actuation of the brake pedal. To counteract an undesired change in the self-steering effect during load alternations, within the scope of the present invention, the torque distribution between the vehicle axles is modified as a function of the gas pedal actuation and/or the brake pedal actuation. In this manner, it is possible to ensure a satisfactory self-steering effect of the motor vehicle.
In routine driving, a first torque distribution between the support torque provided on the front axle and the support torque provided on the rear axle is preferably used, wherein when the first signal allows a conclusion to be drawn that the gas pedal position or the drag torque is above or below a threshold value, and/or the first signal allows a conclusion to be drawn that the gas pedal actuation speed or the drag torque speed, or the gas pedal actuation acceleration and/or the drag torque acceleration, exceeds a threshold value, and/or the second signal allows a conclusion to be drawn that the brake pedal is actuated, a second torque distribution is used for which the support torque provided on the front axle is greater compared to the first torque distribution.
This second torque distribution is maintained for a defined period of time. Following the defined period of time, a third torque distribution is used for which the support torque provided on the front axle is smaller compared to the second torque distribution. This period of time may be selected to be constant or, for example, to be a function of the drag torque and/or the driving state.
The device according to the invention for roll stabilization of a motor vehicle includes a device for measuring or calculating a transverse acceleration of the motor vehicle, and a control and regulation device, which on the basis of the measured or calculated transverse acceleration, generates actuating signals for actuators which are associated with a front axle and a rear axle of the motor vehicle and which provide support torques on the front axle and/or on the rear axle for roll stabilization. The control and regulation device includes a device for determining a torque distribution between the support torque provided on the front axle and the support torque provided on the rear axle on the basis of a first signal which allows conclusions to be drawn concerning the actuation of a gas pedal, and/or on the basis of a second signal which allows conclusions to be drawn concerning the actuation of a brake pedal.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description when considered in conjunction with the accompanying drawings.